- At Visit 1, in steroid-naïve participants, no significant adrenal suppression, defined as a plasma cortisol concentration less than 5 mcg/dL. If adrenal suppression occurs, a 250 mcg corticotropin (ACTH) stimulation test will be performed. Plasma cortisol levels will be collected at baseline, and 30 and 60 minutes after the ACTH stimulation test. Participants must have a cortisol concentration greater than 20 mcg/dL on at least one of the post-ACTH time points